ARM: dts: msm: Fix GLINK interrupts for sdxprairie

GLINK on mdm targets should use the fourth ipc interrupt instead of
the first interrupt. Change glink device tree entry to use SPI
interrupt 114 and mailbox bit 15.

Change-Id: I986cd2c8f86eb06afd43ff28df634bdc6b5f9472
Signed-off-by: Chris Lew <clew@codeaurora.org>